Questions covered in this guide
Qualify the roof before selecting the coating
GAF’s silicone-over-asphaltic guidance calls for moisture and adhesion assessment and a suitable existing surface. Those requirements illustrate why a coating proposal needs evidence about the current roof rather than only a product name and square footage.
Ask what the assessment will answer
Have the contractor identify the existing roof material, the proposed coating system, and the checks needed to determine whether that combination is suitable. Request a written account of any wet or damaged areas they identify and how those areas affect the proposal. Do not assume that an attractive finished coating will resolve concealed defects. The assessment should explain what is being retained and what must be repaired or removed first.
Create an acceptance worksheet
Use rows for existing substrate, moisture findings, adhesion result, surface preparation, local repairs, and the proposed finished system. For each row, record the report or document provided and the professional responsible. Add a decision field: confirmed, needs work, or unresolved. Ask what findings would change the recommendation from coating to another approach. This makes the qualification process reviewable without asking you to perform testing or choose application rates.
Compare qualified alternatives
Request a revised price after the assessment identifies necessary preparation and repairs. Compare that complete scope with any replacement proposal, keeping exclusions visible. Ask for maintenance and future inspection information appropriate to the selected system. The national roofing calculator does not determine coating eligibility or include a verified coating price. A useful next step is a documented qualification result, followed by a proposal that accounts for the condition actually found rather than treating all existing roofs as equivalent.
Putting it into practice
The acceptance worksheet makes coating eligibility an evidence-based step before price comparison. It separates retained substrate, moisture findings, adhesion, and preparation instead of portraying a coating as a universal replacement substitute.
Sources and supported claims
GAF’s silicone-over-asphaltic guidance calls for a moisture scan when qualifying an existing roof.
Source ↗ · national · Checked 2026-10-12
GAF also calls for an adhesion test and a clean, dry, tight roof condition.
Source ↗ · national · Checked 2026-10-12